https://www.afma.gov.au/fisheries-management/declaring-foreign-boat-be-australian-boat#referenced-section-3
What is the legal definition of an Australian boat?
A boat is defined as an “Australian boat” if it satisfies any one of the following 3 conditions (as set out under subsection 4(1) of the Fisheries Management Act 1991):
The boat is operated from Australia and is wholly owned by an Australian resident or Australian company and was built in Australia;
OR
The boat is listed on the Australian
Shipping Register, except if it is owned by a foreign resident and under a demise charter1 arrangement;
OR
The boat has been declared by AFMA to be an Australian boat under subsection 4(2) of the Fisheries Management Act 1991.
If a boat does not satisfy any of these 3 conditions, it is regarded as a foreign boat under the Fisheries Management Act 1991.
1Demise
charter means "the demise, letting, hire or
delivery of the ship to the charterer under a
charter party, by virtue of which the charterer has whole possession and control of the ship (including the right to appoint the master and crew of the ship)." (Shipping Registration Act 1981)
Can my boat be listed on the Australian Shipping Registry?
The Australian Shipping Register is administered by the Shipping Registration Office under the Shipping Registration Act 1981.
A boat may be listed on the Australian Shipping Register (or “Australian flagged”) if:
more than half the shares in it are owned by Australian nationals; or
it is less than 12 metres in length overall and wholly owned or operated by Australian residents or by Australian nationals and residents together; or
it is on demise (bare boat) charter to an Australian based operator.
A foreign-owned boat that is chartered under non-demise arrangements is not permitted to be registered.
Applications to list a boat on the Australian Shipping Register must be submitted to the Australian Shipping Registration Office in the Australian Maritime
Safety Authority. For further details on the application process, please contact the Australian Shipping Registration Office.